Chapter 1: Foundation

Virtual Private Networks (VPN)

• A firewall is an access control device that sits between two networks or two network segments.
• It filters all traffic between the protected or "inside" network and a less trustworthy or "outside" network or segment
• Many firewalls can be used to implement a VPN.
• the user can request a VPN session with the firewall
• The user's client and the firewall negotiate a session encryption key
• the firewall and the client subsequently use that key to encrypt all traffic between the two
• it feels to the user that the network is private, even though it is not.
• With the VPN, we say that the communication passes through an encrypted tunnel or tunnel.